The present invention relates to a structure for supporting fluid pressure cylinders that are used to control pivoting of axles with respect to vehicle bodies.
A forklift includes a body, a rear axle supported by the body, and rear wheels mounted on the rear axle. Typically, the rear axle is pivotally supported with respect to the body. Thus, the axle pivots with respect to the body to constantly maintain traction between each wheel and the ground surface even when the forklift travels along bumpy surfaces. However, the pivotal structure of the axle may reduce the driving stability of the forklift. For example, the forklift's center of gravity may be raised due to the load being carried. In such state, if the forklift is steered in a sudden manner when changing direction, centrifugal force acting laterally on the forklift (lateral acceleration) may tilt the forklift body. Accordingly, an axle locking apparatus has been proposed to stabilize the forklift under such circumstances. The apparatus restricts the pivoting of the axle with respect to the body when a detected yaw acceleration or lateral acceleration exceeds a predetermined value.
As shown in FIG. 4, the apparatus includes a hydraulic cylinder 22, which is located between a body 20 and a rear axle 21. The cylinder has two hydraulic oil chambers that are connected to each other by a passage. An electromagnetic valve 23 is arranged in the passage. The electromagnetic valve 23 closes the passage to stop the movement of hydraulic oil between the two oil chambers. This locks the hydraulic cylinder 22 and prohibits pivoting of the rear axle 21 with respect to the body 20. To permit pivoting of the rear axle 21 relative to the body 20, the electromagnetic valve 23 opens the passage. This allows movement of hydraulic oil between the two oil chambers and thus unlocks the hydraulic cylinder 22.
An upper bracket 24 is welded to the body 20 to support the hydraulic cylinder 22. As shown in FIGS. 4 and 5, the upper bracket 24 has a base plate 27 and a pair of parallel support plates 28 fixed to the base plate 27. An upper pin 25 is supported by the support plates 28 and is parallel to the pivoting axis of the rear axle 21. The hydraulic cylinder 22 has a cylinder tube. An upper anchor 26 having a bore is defined at the top portion of the cylinder tube. The upper anchor 26 is held between the support plates 28 with the upper pin 25 extending through the anchor bore. Accordingly, the hydraulic cylinder 22 is pivotally connected to the body 20.
As shown in FIG. 4, a lower bracket 30 is fixed to the rear axle 21. A lower pin 29 is supported by the bracket 30 and is parallel to the pivoting axis of the rear axle 21. A lower anchor 26 having a bore is defined at the bottom portion of the cylinder tube. The lower pin 29 extends through the bore of the lower anchor 26. This pivotally connects the hydraulic cylinder 22 to the rear axle 21.
The upper bracket 24 is produced exclusively to connect the hydraulic cylinder 22 to the body 20. However, the employment of the single-purpose bracket 24 not only increases the number of components required to support the hydraulic cylinder 22 but also complicates the structure for coupling the hydraulic cylinder 22 to the body 20. Thus, the employment of the bracket 24 results in additional tasks during production of the forklift and thus lowers efficiency.